from math import sqrt
x1,x2,y1,y2=map(float,input().split())
a=abs(x1-y1)**2
b=abs(x2-y2)**2
s=sqrt(a+b)
print(s) from math import sqrt x1,x2,y1,y2=map(float,input().split()) x1 map(float,input().split()) map float input().split() ().split () input split x2 y1 y2 a=abs(x1-y1)**2 a abs(x1-y1)**2 abs(x1-y1) abs x1-y1 x1 y1 2 b=abs(x2-y2)**2 b abs(x2-y2)**2 abs(x2-y2) abs x2-y2 x2 y2 2 s=sqrt(a+b) s sqrt(a+b) sqrt a+b a b print(s) print s x2,y1,y2=map(float,input().split()) map(float,input().split()) x2 y2=map(float,input().split()) map(float,input().split()) y2 a=abs(x1-y1)**2 abs(x1-y1)**2 a b=abs(x2-y2)**2 abs(x2-y2)**2 b x1,x2,y1,y2=map(float,input().split()) map(float,input().split()) x1 y1,y2=map(float,input().split()) map(float,input().split()) y1 s=sqrt(a+b) sqrt(a+b) s
from math import sqrt
x1,x2,y1,y2=map(float,input().split())
a=abs(x1-y1)**2
b=abs(x2-y2)**2
s=sqrt(a+b)
print(s)
